Safety ignition systems



Nov. 15, 1960 F. w. HOLSTEIN 2,960,159

SAFETY IGNITION SYSTEMS Filed Jan. 24, 1956 hermopile Thermopil INVENTOR. [tum/m l7 1%: mw

SAFETY IGNITION SYSTEMS Frederick W. Holstein, Hopatcong, NJ., assignor to The Rails Company Filed Jan. 24, 1956, Ser. No. 561,125

3 Claims. (Cl. 158-122) My invention relates to safety ignition systems for rail and switch heaters.

In general, a rail or switch heater comprises a heater pipe with flame orifices along the rail to be heated, the purpose being to melt snow and ice so as to permit switch operation, for example. Spaced along the heater are a series of inspirators supplying the fuel mixture required. According to my present invention, each inspirator casting is provided with a threaded opening for the attachment .of an igniter housing including therein an igniter, in this case a hot wire ignition coil, and a thermocouple generator or battery comprising a series of thermocouples joined together to provide electrical current when heated, sufficien-t to operate a double acting relay which shuts otf the power supply to the igniter and activates thereby a signal system independent of the igniter, to indicate at the control station that the heater is functioning.

To be effective at a switch, such igniter devices are on both rails and may be installed in pairs and I provide a safety device whereby both heaters must be burning to maintainthe signal indication and yet may indicate a single ignition. The same safety device operates with a single igniter to insure proper functioning of the relay without sticking.

Together with the foregoing, an object of my invention is to provide an ignition device with no moving parts; also a signal circuit independent of the ignition coil and a self-restoring safety system for connecting a plurality of igniters in parallel in the same circuit and effectively controlling them.

With the foregoing and other objects in view, as will be apparent to those skilled in the art as the description proceeds, my invention resides in the combination and arrangement of parts and in the details of construction described in this specification and particularly pointed out in the appended claims, it being understood that changes may be made in the particular embodiment of my invention within the scope of what is claimed without departing from the spirit of the invention.

In the drawings, Fig. 1 is a side elevation illustrative of an inspirator and igniter combination; Fig. 2 illus- ;trates diagrammatically the preferred construction of my igniter and its circuit; Fig. 3 indicates a detail of circuit change. Similar reference characters relate to similar parts in all the views.

In Fig. 1 an inspirator 1 is provided with the usual fuel intake 2, heater pipe connection 3 and a threaded opening into which an ignition device housing 4 may be removably placed, the housing comprising a base 5 having one or more drainage and explosion relief openings 6. An open ended tubular sleeve 7 is removably supported at one end in the base 5 and clamped in place as by set screws 8, 8, the other end of the sleeve 7 having an external thread 9 for detachable connection to the inspirator body.

Mounted in an insulating disk support 10 in each ignition housing is t fixture :11 containing a battery of nited States Patent O 2,960,159 Patented Nov. 15, 1960 "ice thermocouples which may, for example, when heated to flame temperature around 1200 F. provide approximately milliamperes output. Positioned also in support 10 are suitable terminals holding, for example, hot wire ignition coils 12 which may be connected by a control switch 13 in circuit with a source of power 14 through the armature switch arm 15 biased to close the contact 16 and thus energize hot wire ignition coil 12 which ignites the gas mixture within its igniter housing.

The heat of the burning gas within the housing activates the corresponding thermocouples in fixture 1'1 and they supply a surge of current through a by-pass switch 17 to relay 18, by-passing resistance 23. This attracts armature 15 opening contact 16 and closing contact 19, de-energizing ignition coil 12, closing a separate signal circuit and energizing the signal device 20 at the control station. Power for the signal circuit is preferably from the main source 14 as shown in Fig. 2 but may be from a separate source 24 as indicated in Fig. 3.

By-pass switch 17 is normally closed by the bias of a bi-metallic member 21 which is affected by a heater wire 22 across the output of the thermocouple battery. When the relay circuit is energized, this heater wire 22 heats up the bimetallic switch member 21, causing it to open switch 17, thus throwing a safety control resistance 23 in series with relay 18. This resistance is adjusted to relay 18 so as to provide a current drop below the relay requirements unless all thermocouple devices connected to the line are being maintained at output temperature.

Hence, if each thermocouple generator supplies an effective 150 milliamperes and that is the minimum requirement for relay 18 and a pair of igniters are connected in parallel, as in Fig. 2, the ignition of fuel in only one inspirator may actuate relay 18 momentarily and flash the signal device 20, but as soon as the bimetallic arm 21 opens switch 17 and throws resistance 23 into the relay line, the resulting drop in current will cause release of armature 15, closure of contact 16, re-energizing of igniters 12, 12, until both thermocouple batteries supply rated output and thus overcome resistance 23 to supply the requirements of relay 18.

Likewise, even with a single igniter in line, relay 18 may and usually does, require a greater current to close switch 19 than to hold it. The initial surge of current through switch 17 will then actuate relay 18 and resistance 23 is chosen to provide only sufficient holding current when the thermocouples are heated and thus a more sensitive signal control is achieved. Igniter devices, however, in substantially all cases, are provided in pairs, one on each rail, as indicated in Fig. 2 and the hot gases in one heater do not affect the other.

As long as the heaters are operating, the thermocouple batteries 11 are active, current flows through heater wire 22, maintaining by-pass switch 17 in open position and switch 19 closed so that signal 20 indicates full operation. Should either heater fail, whether by wind action, lack of fuel or power, signal 211 will so indicate. However, the ignition system shown and described is selfrestoring, which is desirable in cases of temporary failure by wind action or the disturbance of passing trains.

What I claim is:

1. In a safety ignition system for gas-fueled rail heaters, a pair of igniter devices, each comprising a hollow body member having an open end and adapted to be positioned alongside a stream of fuel and air mixture of a rail heater in igniting and heat receiving relation thereto, an ignition member and a thermocouple generator in each said body member adjacent the open end thereof, a power circuit for said ignition members including a switch, a relay to open said switch including a coil energized by said generators, a control resistance in series with said relay coil adjusted to said relay coil current re- 2,960,159 r s e 3 quirements normally to hold the relay armature but not pick it up, a thermoresponsive switch in parallel with said resistance and by-passing same, said thermoresponsive switch comprising a bi-metal switch arm, a heater vtu're adjacent said switch arm to operate said thermoresponsive switch, said heater wire being connected across the output of said generators, and means to signal the opening of said relay switch.

2. The combination with a gas-fueled rail heater and means to supply a stream of fuel and air mixture thereto, of a safety ignition system comprising a hollow igniter body member having an open end positioned alongside said stream of fuel and air mixture of said rail heater in igniting and heat receiving relation thereto, an ignition member therein adjacent said open end, a power supply circuit for said ignition member including a normally closed relay operated switch, a thermocouple generator in said igniter body adjacent the open end thereof in series with the relay coil of said switch, a control re sistance in series with and adjusted to the current requirements of said relay coil normally to hold the armature but not pick it up, means to bypass said resistance comprising a thermoresponsive switch in parallel with said resistance, said thermoresponsive switch including a bi-metal switch arm and a heater wire adjacent said arm connected across said generator output and signal means to indicate opening of said relay switch.

'3. In a safety ignition system for a gas-fueled rail heater including a fuel supply, an igniter device comprising a hollow body member having an open end and adapted to be positioned alongside a stream of fuel and air mixture of a rail heater in igniting and heat receiving relation thereto, ignition means within said body adjacent the open end thereof and a power circuit for said ignition means, the provision of a self restoring signal control system comprising a thermocouple generator in said igniter body member adjacent the open end thereof, a relay actuated by said generator, a control resistance in series with and adjusted to the current requirements of said relay coil normally to hold the armature but not pick it up, a by-pass switch across said resistance, means across said generator output controlling said by-pass switch adapted when energized to open said switch and throw said resistance in line, a switch in said power circuit controlled by said relay and signal means to indicate the position of said last named switch.

References Cited in the file of this patent UNITED STATES PATENTS 2,266,185 Fillo Dec. 16, 1941 2,409,492 Jones Oct. 15, 1946 2,644,657 White July 7, 1953 2,720,255 Bishofberger Oct. 11, 1955 2,735,483 Brodbeck et a1. Feb. 21, 1956 

